Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Artificial fluorescent or incandescent lighting is typically modulated by the mains frequency of the alternating current (AC) electrical power from the grid. Thus, in the US, lighting is typically modulated at 120 Hertz (due to 60 Hertz utility waveform reaching maximum voltage difference twice per cycle), and in Europe, lighting is typically modulated at 100 Hertz (due to the 50 Hertz utility waveform).
In conventional electronics systems, individual electrical components may vary due to variations in the fabrication process. For instance, integrated circuit components may have different values due to variations in the die process that forms the chip. Such process variations can be accounted for, in practice, using at least two precision components, which can be used as references to calibrate the remaining components. One precision value can be provided from the bandgap voltage of silicon. Another precision value may be provided using an off-chip precision resistor that has been separately calibrated. Using the combination of the silicon bandgap voltage and the precision resistor value as references, the remaining components on the chip can then be characterized and calibrated for. In other examples, instead of a precision resistor, a precision timing reference may be provided by a quartz oscillator or another precision component connected to the chip. The precision timing reference can then be used in combination with the silicon bandgap voltage to calibrate other components.